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    <div id="app">
        我是没有v-once指令的：{{ n }} <br>
        我是有v-once指令的：<span v-once>{{ n }}</span> <br>
        <button @click="n++">点我+1</button>
    </div>

    <script src="../JS/vue.js"></script>
    <script>
        new Vue({
            el: '#app',
            data() {
                return {
                    n: 1
                }
            },
        })
    </script>
</body>

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